One type of connector has a shell of rectangular cross section which surrounds a modular insert containing a body of insulative material and multiple contacts mounted on the body. A ground plane is sometimes necessary, which is connected to the shell, to provide electromagnetic interference shielding when the connector is unmated from another connector. The ground plane also facilitates the termination of filter pin or electromagnetic pulse dissipating contacts. The modular insert not only must be securely held within the shell, but must be able to "float" or shift position laterally by perhaps 0.010 inch to enable the contacts to shift position during mating with contacts of another connector. A simple means for retaining an insulative body of a connector within a shell, especially a modular insert, which also provided an electromagnetic shield and ground plane connected to the shell, which enabled "floating" of the insert relative to the shell, and which enabled the easy removal of the insert from the shell and its replacement, would be of considerable value.